The most related work concerning the PenFun method is [13], in which the authors transform the rank-one constraint into a concave penalty in the objective function and then handle the transformed problem with the convex-concave processing (CCP).
This essentially ranks the scores (with missing/could-not-perform set as the highest rank and missing-at-random left blank) and then inverse-normal transforming the ranks.
Outliers above or below 3 SD from the mean were excluded and scores were normalized by transforming the ranked data to the quantiles of a standard normal distribution using the van der Waerden (1952) transformation.
This methodology is based on the ranking of differences between health states combined with an associated scaling model that transforms the individual rank data into group values on the interval level.
This is most likely due to the robust but less sensitive rank transform, the need to avoid linear artifacts in data imputation, and the observational nature of the study.
Passage of health insurance reform has already transformed the progressive rank and file.
We conducted a multiple regression analysis to control for age and gender, after rank-order transforming the rating scales.
Caterpillar plots are forest plots which have been transformed by the ranking of studies in order of increasing study or group specific effect size.
We then numbered the values in rank order from 1/n to 0.999 and used the NORMSINV function in Microsoft Excel to transform these ranked values into the standard normal cumulative distribution (mean of zero and a standard deviation of one).
Transforming the frailty into ranks allows to study the posterior distribution of the rank of a specific clinic.
